DIVING BEHAVIOR OF THE GREY-HEADED ALBATROSS

Foraging grey-headed albatrosses spent 86% of the night but only 20% o f the day sitting on the seal most diving activity occurred during day light. During;he brood-guard period of nesting, peaks of diving activi ty occurred at midday and dusk. During the subsequent chick-rearing pe riod, however, diving was mainly al dawn and dusk. Of 485 dives measur ed, the depth averaged 0.74 m, with maximum depth at 6.5 m. On average grey-headed albatrosses dived 24 times during a five day foraging tri p. Dive depths increased towards midday, probably as a function of the birds' visual acuity rather than due to vertical migration of their p rey. We estimate that grey-headed albatross es may obtain 30-45% of th eir daily food requirements by diving.